Pontiac Repair: 2000 4cyl Grand am sputtering at idle/cruise, fuel pump filter, possability

Question
2000 Grand Am SE 2.4L
So i just replaced the fuel pump/filter and line 'cause the car just stalled out, twice driving down the highway. Problem seemed fixed. But now (2 months later)the car at idle and cruise (low load) is sputtering. the RPMs drop about 4-500 rpm every 4-5 seconds. Doesn't stall at a stop but if it gets worse it will. Thougths?

Answer
Hi Darrin:

has all this happened since the water pump was installed? If so there is a possability the cam timing was not correct afetr the pump was replaced. The timing chain runs the water pump and if yout off a tooth or 2 on the cams it will run bad. If that is not the issue I would take a look at the throttle body and plate if they are dirty and carboned up it can cause all kinds of idle issues. The throttle body will not cause a stall at highway speeds though neither will the timing. I would suspenct possably a fuel pump is acting up for the high speed stalling. When was the last time the fuel filer was replaced? good luck:)